Electric switch



Dec. 27, 1932. c. E. vNICHOLAS ELECTRIC SWITCH Filed July 2. 195oATTORNEYS Patented Dec. 27, 1932 PATENT OFFICEk CHARLES E. NICHOLAS, orLosANGnLEs, CALIFORNIA ELECTRIC SWITCH Application mea Jury a, 1930.serial No; 465,255.

This invention relates to electrical alarms and electrical 'alarmcircuits for use in con nection with doors or other closures such as thedoors of buildings, safes or vaults and is particularly adapted for useon safes having dial combination locks.

One embodiment of my invention herein disclosed is a device particularlydesigned to be hung. on the knob of the dial of a combination lock andis so constructed that any attemptto remove the device or any movementof it will so operate on an electrical cir- .cuit lin which itisconnected as to actuate the alarm. Another embodiment is the circuitin 5 which said deviceis connected, the circuit also being an importantpart of the linvention.

The signal devices used may be of any type capable of being operatedlelectrically such as lights, bells or horns, or any other desired typeof visible or audible signal.

An embodiment of my invention is shown f in the accompanying drawing inwhich:

Fig.1 is a front elevation, the top of the casing beingk removed. f i nv A Fig. 2 is a vertical sectional View along the line 2*- X of Fig. 1.

Fig. 3 is a rear elevation with the insulat`A ing back removed. l

Figs.' 4and 5 are horizontal sectional views along the line 4*--4 ofFig, 1 and 5*--5X ofFig. 2, respectively. f

Fig. `6 is a schematic diagram showing my electricalci-rcuits andcertain other features of the system. i

Fig.y 7 is a detail drawing of the internal insulating block on areduced scale.

An important part'of my invention is the provision of a devicedesigned'to hang over the knob of a door tobe protected, forexample,the'dial knob of a safe and which I shall for conveniencedesignategenerally as the the contact box having a metal cover 1, which may beformed by casting, stamping or otherwise, and may have anyV suitabledesign formed on its surface as by embossing, as illustrated at 2.y Thiscover has a back 4, of

dielectric material, which is removably secured by means of bolts 5.Between the cover 1 and the back 4 is located an insulat-f ing blockhaving an upper partk provided with holes through which' the bolts 5pass. 60 Itis also providedwith tapped holes 9 to accommodate the screws10. The lower part 7 ofV the insulating block fills the lower portion ofthe cover 1 and is rconstructed in a manner hereinafter described. Asthe block is moulded in one piece, it has side members 8 (see Fig. 7). t

Referring to Fig. 3, conducting strips 11 and 12v areadjustably's'ec'ured to the ends 6 and 7 4of theinsulating block. Thesecon- 0 ducting strips are cut yaway on thin proXimate faces to form anopening 14 which is wide at the bottom and gradually decreases in widthVtoward the top. ,The opening 14 is of such size'and shape 7a that thecontact box can be slipped over the dial knob 15 of a staf-e and droppcdy down until the conducting strips 11 and 12 rest on the neck 16 ofthe knob 15, thus forming an electrical Contact through strip 11, knob15 and BO strip 12. Strips 11 and 12 being adjustable, the opening 14can be changed to accommodate variations in the size of knobs. Formed inthe lower end 7 of the insulating block is a recess 17 in which isfastened a conducting spring 19 by meansof the screw 20. This spring 19carriesr on its back a strip of insulation 22, to prevent electricalcontact between spring 19 and the knob 15. Extendy ing vertically in thebottom 7 of the insulating block yare openings 24, 25, 26, and 27 topermit the insertion of circuit wires.

Referring particularly to Figs. 2, 3 and 5 there is formed in one faceof the insulating r block a groove or raceway 29. This raceway is lowerat its central point than at the ends, as shown in Fig. 3, and itsbottom slopes downwardly in the direction of the insulating back 4, asshown in Fig. 2. The ends of the;

raceway` are closed by the sides ofy metal'100 cover 1 and its rear sideis substantially closed by the contacting strips 11 and 12 and by asmall piece of insulation 32 inserted between the bottom edges of strips11 and 12.

In the raceway 29 is a metal ball 30 which is free to roll in theraceway under the inuence of gravity. V

Having thus described the construction of the contact box, I shall nowexplain how it is utilized in my alarm circuit. In Fig. 6 I show asource of electric current which may comprise the batteries 40 and 41,or may consist of a single battery having an intermediate tap 42. Thissource of current supplies both the control circuit and the alarmcircuits.

The control circuit is indicated in heavy lines (Fig. 6) and comprisesbattery 40, wire 44, alarm 45, wire 46, spring 19, cover 1, wire 47,magnet 48, wire 49, strip 12, knob 16, strip 11, wire 50, switch blade51, wire 52, alarm 54, wire 55, battery 41 and connection 42.

I have shown two alarm circuits, but any number may be used. The firstcircuit is as 1`ollows: battery 40, wire 44, alarm 45, wire 57, switchblade 59, wire 60, Contact 61, armature 62. wire 64 and batteryconnection 42.

The second alarm circuit is battery 41, wire 55, alarm 54, wire 52,switch blade 51, wire 65, contact 66, armature 62, wire 64 and batteryconnection 42.

It will be noted that when the contact box is not attached to an objectthe control circuit is open in the box at two points, first, between thespring 19 and the cover 1, as is shown in Fig. 2 by the releasedposition of spring 19, shown in dotted lines at 22'; second, betweenstrip 11 and strip 12, as these strips are insulated from one another.When the contact box is hung upon the knob, as shown in Fig. 2, thetirst circuit opening is closed by the Contact of spring 19 with cover 1resulting from the pressure of the knob 15 against the insulating strip22. The second circuit opening is closed by the contacts made by strips11 and 12 with the knob 15, as is shown in Figs. 3 and 4.

It, therefore, appears that as the control circuit is closed at twopoints when the contact box of my protective device is hung over theknob ot a combination lock dial, conversely the removal ot the contactbox from the knob will open the circuit at two point-s. The controlcircuit may also be opened and closed through the switch blade 51 (Fig.6). This switch blade is part of an ordinary doublepole-single-throwswitch to which I have added an intermediate contact 67. lVhen thecontrol circuit is closed through the contact box and by the engagementof blade 51 with contact 67, current flows through the coil of themagnet 48, energizes that magnet and attracts the armature 62. I haveprovided a means whereby a signal is given upon the contacting of theswitch blade 51 with the contact 67 provided that the control circuit isclosed, energized and ready to operate. This means consist-s inattaching a clapper 69 to the armature 62 which will strike a bell 70when the armature 62 is attracted by the magnet 4S and drawn out otcontact with the contacts 61 and 66. It will readily be seen that unlessthe control circuit is closed and unless there is current flowingsullicient to operate the system, no signal will he given by the bell70. This signal, therefore, is a completo test of the operativenessofthe alarmas soon as the blade 51 makes connection with the contact 67and before the complete closing of the switch connects the alarmcircuits which operate the alarms 54 and 45.

I shall now explain how my system assures that there can be no tamperingwith the lock of a sate without giving an alarm. It is obvious that thesame protection is afforded to any lock to which an adaptation of theembodiment herein disclosed may be attached. The batteries, alarms andmultipole switch are placed in any desired location, preferablyconcealed.

The contact box is attac ied toa length of four wire cable so that itmay be conveniently lo' cated nearthe obj eettobe protected. The cablecontains the wires 46, 47, 49 and 50. After the sate or other door hasbeen closed and locked, the contact box is attached to the dial or otherknob by inserting the knob through the aperture between the strips 11and 12 and the contact box is lowered as far asit will go. This closesthe circuit at two points, as has reviously been described. The contactbox an in a. vertical position so that the metal ball 30 rests at thelowest point of the raceway 29. The switch 51-59 is then closed untilthe blade 51 makes connection with the contact 67, and if the controlcircuit is in working order and supplied with current, the magnet 48will attract the armature 62 which will cause the striker 69 to tap thebell 70. This shows that the system is in working order and the switchmay then be completely closed.

Anyone desiring to operate the dial of the lock must either remove thecontact box or tip it to one side or the other in order to see theindication on the stationary ring 71 (Fig. 2) with which the numbers ofthe combination must be registered to unlock the safe.

If the contact box is lifted a fraction of an inch, the contact throughthe strip l1, knob 15 and strip 12 is broken. If the box is furtherlifted, the spring k19 will be released and the contact broken betweensaid spring and the metal cover 1, which assures the opening of thecircuit even though the strips 11 and 12 or the wires thereto have beenshort circuited.

It the contact box is not raised but is tilted to either side, the metalball 30 will roll in the raceway 29, either to the right or left, andmake contact with the metal box 1 as shown in Figs. 3 and 5 at 30 andthrough either strip 11 or strip 12 and the metal box 1 complete a 48;cutting wires 46, 47, 49 or 50; crossingl shunt circuitacross the magnet48 which will deenergize it.

An attempt to disconnect the alarm 54, or the alarm 45, or any otheralarm in the control circuit, will open the control circuit and likewisedeenergize the magnet 48. n Any invention adapted to a specific use, itis obvious that man modifications may be made without departing from thespirit of the invention.

What I claim is:

1. Circuit closing means for an' electric other attempt to open thecircuit as by cutting alarm device adapted to be loosely hung on thewires forming part of the control circuit, will have the same eect.

lVhen the magnet 48 is deenergized and the armature 62 is thereforereleased and, under the influence of its spring 72, makes contact withthe contacts 61 and66, kthe two alarm circuits previously described areclosed. Upon the closing of these circuits the alarms will be actuatedby the current from the bat teries 40 and 41, or other source of currentsupply. It will thus be seen that if one alarm is disconnected, theother will immediately be caused to ring, and by placing the severalalarms so that it is not possible to disconnect themk simultaneously,the operation of an alarm is assured. y

Cutting or short circuiting the cable of the contact box will also soundthe alarm as any one of the following operations will either open thecontrol'circuit or shunt the magnet either wires 46 or 47 with wires 49or 50. Any metallic connection between the met-al cover 1 and the safewill likewise shunt the magnet 48 when the Contact box is in operativeposition and the knob 15 is in contact With strip 12.

In order that the current through the magnet 48, which must also ilowthrough the coils of the alarms in the control circuit, as the bells 54and 45, shall not actuate the alarms, it is only necessary to choosealarms, an electromagnet, and current potential such that the currentpassing through the coil of the magnet shall be less than thecurrentrequired to operate the alarms. It will readily appear to thoseskilled in the art how this may be done by the choice of a magnet havingsuitable resistance and alarms designed to operate at a certain voltage.

My circuit arrangement is such that the alarms will continue to soundVin the case a metallic knob comprising a metallic casing, a pair ofconductive plates insulated from said casing and spaced apart with theiradjacent edges convergingly disposed upwardly and forming with eachother an upwardly diminishing aperture adaptedfto receive said knob atits lower end and bridging of which is effected by engagement of theshank of the knob' with said edges of said plate upon lowering thecasing thereof.

2. Circuit closing means for an electric alarm device adapted to beloosely hung on a metallic knob, comprising a metallic casing,conductive plates therein, insulated from said casing and from eachother and forming with each other an upwardly diminishing aperturewhereby the device may be slipped over said knob and lowered until the.edges of said plates yboth engage the neck of said knob;

In testimony whereof, I have signed this specification.

CHARLES E. NICHOLAS.

Where the contact box is tipped or displaced cuits established throughthe armature 62 will continue to actuate the alarms.

ioo

While I have shown an embodiment of my l a

